1. Field of the Invention
This invention pertains to the initialization of electronic computer components and, more particularly, to a power on/reset strap for a high speed circuit.
2. Description of the Related Art
Computers typically include a number of integrated circuit devices, or computer chips, that may be operated in more than one configuration. The computer is designed to use the chips in only one particular configuration and so the chips must be "initialized" or "setup" whenever a user turns the computer on or resets the computer. A chip is usually initialized by providing certain electrical signals to the chip, the chip previously having been programmed to configure itself in response to these signals. The circuitry used to generate initialization signals is frequently referred to as the "initialization strap."
These initialization signals are external signals. The initializing external signals are frequently received by the chip on memory address bus lines, although other types of signal lines are sometimes used. The individual external signal lines are tied high or low using "resistor pull-ups" or "resistor pull-downs," respectively. When a signal line is tied high using a resistor pull-up, the chip reads the signal as a digital 1 during the initialization process. Similarly, when a signal line is tied low using a resistor pull-down, the chip reads the signal as a digital 0 during the initialization process. As used herein, the terms "high" and "low" will be used to refer to a signal representing a digital 1 or 0, respectively. Thus, the signal line is "strapped" high or low. The chip therefore receives the configuration signals as soon as power is provided whenever the computer is turned on or reset, and automatically configures itself.
However, this type of resistive loading on signal lines poses significant problems as operating frequencies increase. In fact, at operating frequencies of 66 MHz and higher, this resistive loading becomes a major concern and degrades system performance. Thus, there is a need for a new technique to provide initialization signals to individual chips when a computer is turned on or reset.